Are you happy at your job? If you’re like more than half of Americans, you’re not fully satisfied with your job. That statistic may sound pretty abysmal, but that’s the highest job satisfaction has been in more than a decade. But, it begs the question: Why are so many people unhappy at work?

It shouldn’t surprise you to learn that an increase in happiness is correlated with an increase in productivity (up to 12 percent, according to one study), and that your job satisfaction could even impact your health later in life, increasing or reducing your risk for chronic health conditions. But what is it that makes you happy at work? Does it boil down to having a more positive attitude? Is it finding your “one true calling”? Or is it merely the result of luck?

Now in its sixth year, the annual World Happiness Report strives to objectively measure happiness around the world, and analyze the root causes for that happiness. In its latest 2017 report, Norway’s citizens topped the list as being the happiest in the world, which is attributed to high marks in the following categories:

Income

Life expectancy

A close friend or relative

Generosity

Freedom

Trust

Of these, income, freedom and trust all relate to professional responsibilities. The report delves into more specifics related to happiness at work, analyzing self-reported measures of happiness and well being (which are distinct concepts treated somewhat interchangeably in this report) that represent 98 percent of the global population.

Employment is good. You may feel unsatisfied with your job at the moment, but you’d be far unhappier without one. The report shows, without variation, that unemployment increases unhappiness steadily over the course of the unemployment period. The longer you’re out of work, the less satisfied you’ll be with life.

More income is better. You won’t be shocked to learn that higher income leads to higher feelings of happiness—but only up to a certain point. A study from Princeton confirmed this effect back in 2010, calculating that once you reach about $75,000 in annual income (as a single earner—that’s about $83,000 today), more income doesn’t make you any happier.

Work-life balance is a strong predictor of happiness. Spending more time with family and less time in the office, with less demanding work is a good thing—and with 24 percent of the American workforce working from home at least some of the time, we may be moving in a positive direction here.

Variety and education are valuable. If you do the same thing every day, you’re going to be unsatisfied. Workers with some variety in their work, and those who have the opportunity to learn new skills regularly report higher levels of happiness and well being.

Autonomy leads to satisfaction. For the most part, having more control over your actions can also make you happier at work. Being given autonomy gives people more freedom, one of the key factors for happiness overall.

Job security and safety matter. If your job puts you in danger, or has significant consequences for your health, your happiness is going to decrease. Similarly, if you feel that your job is in jeopardy or that you’ll be unemployed in the near future, you’ll also feel less satisfied with your work. Stable, safe jobs are the ones that yield the most happiness.

Social capital is a moderate predictor of happiness. Though less important than factors like income, work-life balance and variety, social capital can also influence your happiness at work; getting along with your coworkers and engaging in collaborative exercises can make you more satisfied.

Not all types of employment are the same. The report also suggests that different types of employment yield different effects on happiness, mostly for reasons related to the above criteria; for example, self-employed people tend to report lower happiness, in part because of lower job security than full-time employees.

According to a recent study by Oregon University, a happy home life can result in an increase in immersion and productivity, leading to a happier work life. Specifically, they found that workers with an active sex life reported higher levels of engagement and satisfaction than those with strained relationships or other stressors at home.

As much as we try to separate our personal and professional lives, there’s no denying that there’s a correlation here. Failing to address your satisfaction in one area can cause a self-perpetuating spiral; dissatisfaction at home leads to dissatisfaction at work, which leads to even more stress at home, and so on.

Do you need to follow your bliss to be satisfied with your work? The answer is a resounding “no.” Ben Horowitz’s commencement address to Columbia University in 2015 illustrates some of the main issues with this idea. Namely, passions are hard to prioritize, they tend to evolve over time (especially when you’re working on them for 40 or more hours a week), it leads to self-centeredness, and your passions don’t necessarily reflect what you’re good at—or what’s in demand.

What’s even more important is that the overall appeal or industry of your work doesn’t appear to modulate your satisfaction with that work—instead, it’s factors like income, work-life balance, and autonomy that lead to satisfaction.